Update for new recent-txs endpoint plus misc fixes

[iskay]

Before merging, we should wait on namada-net/namada-indexer#429

The response format of the indexer recent tx endpoint is a little different than what was used for #26, so this PR updates the Masp Transactions page to work with the new format. Functionality is unchanged.

Also reworked the Recent Transactions page to use the new endpoint:

See preview here: https://deploy-preview-2--explori.netlify.app

Also includes a few small misc fixes:

• fix a bug where the searchbar was refetching the validators/all query repeatedly on every page even when not requested
• add direction (sent/received) to the tx history when viewing an account
• update the account balance and wrapper tx queries to work with the changed response format in the next indexer release